The goal of this project is to better understand the mechanism of mechanochemical transduction by microtubule-based motor proteins. The subject of this proposal is the ncd protein from Drosphila melanogaster - a member of the kinesin superfamily of microtubule motor proteins that has one or more human homologs. Our specific aim is the X-ray crystallographic determination of three-dimensional structure of the ncd motor domain. Since no structure has been determined for any member of the kinesin family the results obtained from this work should be applicable to the motor proteins of higher eukaryotes and expand our understanding of microtubule based motility in general.